Webalizer and countries unresolved

For some accounts on one of our servers, Webalizer does not show its visitors by country but instead it shows "100% unresolved".
I think this has something to do with the fact that these accounts were created a long time ago, when the Tweak setting was not set to "resolve hostnames". Later on the Tweak setting was changed to "resolve hostnames" but for some reason those accounts were not altered.

Is there a possibility to have Webalizer resolve hostnames for those accounts again?

I've searched the forum, but could only find old topics of several years ago and they described problems with all accounts on that server...